Push button switches incorporating lighted displays have been used in a variety of applications such as on amusement, gaming, and vending machines. Such switches are typically comprised of a push button, an opaque legend plate, and a back light to illuminate the legend plate. This method only accommodates a single color background with a single stationary message or graphic.
A more recent configuration of an illuminated pushbutton switch used primarily in instrumentation includes a push button, a liquid crystal display (LCD) panel, and a back light to illuminate the liquid crystal display panel. Alternatively, it is known to mount the light that illuminates the liquid crystal display panel to the side of the panel. Such a push button switch has been used to convey information, such as the function of the push button switch, to the user.
The use of a liquid crystal display panel in a push button switch has a number of problems. For example, a liquid crystal display panel has a very narrow viewing angle. A narrow viewing angle is desirable for some applications such as computers where the user often does not wish the contents of the computer's screen to be seen by anyone other than the user. However, in many applications, such as where the display is being used to advertise information, a narrow viewing angle is a detriment.
Also, a liquid crystal display panel has a relatively slow response time, typically referred to as latency. This problem is exacerbated at low temperatures and, therefore, supplemental heating may be required for low temperature applications.
Moreover, a liquid crystal display panel requires backlighting, which adds to the cost of a push button switch and which also adds to the power consumption of a push button switch using a liquid crystal display panel.
The present invention is directed to a push button switch which overcomes one or more of these or other problems.